Stock gripping means



1939 s. B. MARTIN v 2,169,107

STOCK GRIPPING MEANS Filed Nov. 18, 1937 2 Sheets-Sheet 1 a [ZZ- 5 INVENTOR.

STQDDARD B- MART/N ATTORNEYS Auvg- 1939 s. B. MARTIN 7 2,169,107

' STOCK GRIPPING MEANS Filed Nov. 18, 1937 I ,2 Sheets-Sheet 2 V m m E V m 5TODDA 78D 3- NAPT/A/ BY C 44. ATTORNEYS Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE 11 Claims.

My invention refers to automatic screw machines and the like and relates more particularly to automatic stock feeding means therefor by which lengths of stock in end to end relation may be fed intermittently toward the tool.

It is one of the objects of this invention to provide means to automatically and intermittently feed bar stock lengths through'the stock reel and the pusher tubes and collets without interruption to the operation of the machine.

A further object resides in eliminating feeding fingers and in providing simple means for holding the stock in the pusher tubes and feeding the stock forwardly upon forward movement of the tubes, by providing either as a structural part of the pusher tube assembly, or as a separate unit, a holding ring and resilient means for normally applying a lateral pressure against the ring so as to cause it to grip themetal of the bar stock during the feeding movement of the pusher tubes.

A still further object of the invention is to construct a stock feeding unit which may besecured to one or both ends of a pusher tube or to the forward end of the feed pipes on the stock reel to provide automatic intermittent feeding of the stock to the spindles of the machine without re-.

chucking operations.

Other objects ofIthe. invention consist mag terially reducing stock waste, feeding positively and allowing no rebound through the pushers.

Also, by my invention, thestock is firmly held by the feeding ring while the pusher tube approaches or is in forward position, but such hold is released upon retraction of the tube, thus preventing undue strain to retract or mar the bar stock which has beenfed forwardly. In this manner, operation of the stock feeding mechanism is positive and automatic at each index of of the stock, back the spindle carrier.

It is also an important object of my invention to apply slight pressure to one side of the holding ring. The application of such pressure affords positive control over the stock holding means at all times. 7

Another object consists in materially increasing the capacity of the machine for any predetermined diameter pusher tube. This is accom plished in accordance with my invention by the provision of interchangeable bushings and holding rings of selected internal diameters and by the elimination of projections or obstructions such as studs, flanges, or screws within the push er tubes which extend inwardly of the normal inside diameter of the tubes. By the elimination of internal projections, screws, studs, or the like,

weakened tube portions are also eliminated.

Other objects and advantages of my invention will become more apparent as the following de- 5' ing ring is shown in holding position as when the 157 tube approaches or is in its forward feeding position.

Figure 2 is a view similar to that of Figure 1 and shows the relation of the parts as the tube is being retracted.

Figure 3 is a perspective view of one form of holding ring made in accordance with my invention.

Figure 4 is a perspective view of another embodiment of the holding ring.

Figure 5 is a longitudinal section through a unit embodying my invention and which is so constituted that it may be secured to an end of the'pusher tube or the forward end of the stock feed'pipe on the stock reel. By providing these 30 units in right and left hand threaded shanks they may be applied as above and also to the rear end of the pusher tube.

Figure 6 is a broken section of an assembly for intermittent automatic stock feeding, the same il 35 lustrating its application only to one of a series of stock feed pipes and respective pushers.

Figure 7 is a perspective View of an automatic screw machine taken at the feed end and showing the stock reel and pusher tube assembly with my 40 invention shown applied in use.

Figure 8 is a sectional view taken along line 8-8 of Figure 1, but instead of showing the bar stock projecting through the ring, I have in this view shown the end of the same in a position in 45 which its end is about to enter the holding ring.

Referring-first to Figures 1 to 3 inclusive, I will proceed to describe the first embodiment of my invention illustrated in these figures of the drawings.

As shown, this embodiment is constructed as a part of the pusher tube assembly, the pusher tube being-indicated at l. The stock 2 is fed axially through the tube and is supported at the forward end of the tube in'the bushing 3. The bushing 3 55 is removably fitted into the forward end of the tube and abuts against the shoulder 4.

The feeding ring is indicated at 5 and, in the present embodiment, comprises an annulus of metal, the side walls of which converge from one point to a diametrically opposite point. Preferably the plane of the wall 6 is at right angles to the axis of the ring while the wall I is inclined slightly to this plane so as to produce a ring having a larger cross sectional area at one point and smaller areas at other points around its circumference. It will be noted that the inner wall of the ring is serrated or roughened as at 8 to provide biting projections along the outer edges of the said wall.

In further carrying out my invention I provide means for exerting pressure against a side wall of the ring to normally tilt the ring' slightly to stock holding position. As illustrated, one form of such means may comprise a coiled spring 9 which abuts the ring side wall which is normal to the tube axis. The pressure thus exerted upon the ring need not be great and a relatively light spring may be used, it being sufiicient that the ring be tilted as shown in Figure 1 in order that it may engage the stock bar at I and II under slight pressure.

A nut I2, in the application shown in Figures 1 and 2 is provided with left hand threads I3 and is threaded into the forward end of the pusher tube I abutting the spring 9 as shown; Suitable openings or notches'may be provided in the nut as at I4 for engagement by a wrench or tool.

Figure 1 represents the parts in their respective positions as the pusher tube moves to the right to feed the stock to the collet. In such position the holding ring 5 is slightly tilted in a counterclockwise direction'underthe light pressure of the spring 9 so that the serrated edges'of the inner wall of the ring will bitingly engage the bar stock at the points I9 and II which are substantially diametrically opposite one another.

Figure 1 is slightly expanded beyond the degree of expansion of the lower portionand that theportion of the ring having the least cross sectional area is the portion immediately adjacentthe upper or expanded portion'of the spring.

the pusher tube I. capacity of the tube is maintained at a maximum insofar as the spring is concerned.

The spring 9 need only exert'a light pressure against the side wall of the ring sufiicient to urge it to tilted position. In that position movement of the pusher tube to the right in Figure- 1 will cause the ring to bind or grip the bar stock at points I0 and I I and firmly hold the stock therein without slippage or damage to the stock and will advance the stock with the tube for the full'stroke or movement of the tube.

The bearing block or bushing 3, the ring 5 and the spring 9 are all readily removable from within the tube by merely unscrewing and removing the nut I2. permits a wide range of stock sizes for use in a pusher tube of given inside diameter and thereby increases the capacity of the tube. For instance, if it is desired to use stock having a larger diameter than that shown in Figure 1, the operator inserts a bushing and holding ring having the proper inside diameter for the selected size stock.

Thus it willbe seen that the top portion of the spring 9 in This is a desirable feature in that it- It will be seen from the drawings that one can approach very closely to the inside diameter of the pusher tube in selecting stock since there are no pins, screws, flanges or other projections secured to or operating through the pusher tube wall and extending inwardly beyond the actual inside diameter of the main portion of the pusher tube.

Both the spring 9 and the nut I2 have an inside diameter approximately that of the tube itself and need not be replaced by similar members having smaller diameters when smaller diameter stock is being fed through the tubes, since these members have no contact with the stock. It is an important advantage of this invention that the stock capacity of the pusher tube may be greatly increased. Furthermore, by the construction shown, the same can more easily be cleaned of chips anddust which may collect within the tube and settle to the bottom thereof.

In Figure 2 I have illustrated the relative positions of the parts when the tube is retracted for the next feeding position. During movement of the tube to the left in Figure 2; and while the collet (not shown) firmly holds the forward end of the stock bar, the compression of the spring 9 will tend to become uniform around its circumference since the upper or thinner part of the ring at I5 is tilted back in a clockwise direction to the upright position shown, thus releasing its hold on the tube at the points I0 and I I.

In Figure 3 I have illustrated in detail the ring shown in Figures 1 and 2 although in Figure 4 I have illustrated a modified form of ring which by its particular construction, permits the major portions of the ring side walls to lie in parallel planes as at I6 and I1. However, in this form I provide a projection I8 extending laterally from one side of the outer circumference of the ring. This projection may be formed integral with the ring as shown, or it may be in the form of.a stud or pin (not shown) projecting laterally of the ring to engage the end wall of the bushing 3. The inner wall of the ring is serrated as at 8 in like manner to that shown in Figure 3.

In Figure 5 I have illustrated as another embodiment of my invention, a reversible or interchangeable pusher unit which is compact and simple .of construction and which is particularly useful, in providing automatic intermittentfeed for machines of this type.

This unit is complete in itself and is capable of use at one end of a .pusher in the manner described in connection with Figures 1 and 2. When it is desired to convert the machine to feed aligned lengths of bar stock intermittently, these units may be employed as indicated in Figures6 and "I, that is, one at each of the forward ends of the stock reel tubes, one at the spool ends of each of the pusher tubes and one at the collet ends of each of the pusher tubes.

This conversion may be done merely by slightly altering the pusher tubes furnished with machines now in use or the machines may be furnished with pusher tubes and my removable pusher units complete.

I will nowproceed to describe in. detail the structure of the pusher unit illustrated in Figure Each unit may comprise a cylindrical body or threaded end of the body is provided to receive a retaining nut l2. I 7' A bushing 3 is insertable in the body from the internally threaded end and abuts a shoulder 4 in the body. v

In Figure 5 I have applied'the type of holding ring I! illustrated in Figure 4 assembled in the unit although the type shown in Figure 3 may be used if desired with equally good results. The ring and bushing 3 thus assembled are of substantially the same internal-diameter to accommodate the size of stock bar selected. Other bushings and holding rings having respectively larger or smaller internal diameters are interchangeable With the members herein illustrated and it will readily be observed that, since the least internal diameter of the body 20 is approximately that shown at 23, the internal diameters of the bushing and ring may be substantially increased close to that at 23, thereby materially increasing the stock capacity of the unit.

By such an arrangement the capacity range of the entire machine is increased, without the necessity for rechucking the machine.

The spring 9 and the nut I2 complete the assembly of the unit. When the unit is tobe applied to the forward end of. the pusher tube or the forward end of the stock reel pipe 21, as indicated in Figure 6,'the threaded ends 2| and 22 are formed with left hand threads to more efiectually retain'the nuts and units in home position. When the unit is to be applied to the rear end of the pusher tube as shown in Figure 6, it is desirable to provide these ends with right hand threads because the unit is in a reversed position, that is, its axis is turned through 180 from its position-in Figure 5. When the unit is thus applied to the rear or spool end of the pusher tube, the holding ring must be reversed in the unit, that is, its relative position to the nut l2 and spring 9 is between the same, While in the position indicated in Figure 5, the holding ring is positioned between the bushing 3 and the spring 9.

In the reversed position the holding ring is turned so that the projection l8 engages the inner face of the nut l2 at 24 while the spring 9 exerts a pressure upon the opposite face of the ring sufficient to tilt the ring slightly to the left from the vertical as illustrated in the center unit in Figure 6.

When the holding ring is in this reversed position, the portion of the spring diametrically opposite to the projection I8 is flexed out of the vertical to the left and thus causes the points 25 and 26 of the ring to bitingly engage the bar stock. It will be observed in Figure 6 that, in each of the units assembled along the stock line of travel, the respective holding rings are tilted to the left from the vertical. In this position movement of the pusher tube and unit assembly including units B and C may be moved to the right in the figure to advance the stock bar through the collets (not shown). During such movement to the right, the unit A will likewise permit the stock bar 2 to be fed manually or otherwise through the pipe 21 to the right.

As the pusher tube and unit assembly including units B and C are retracted to the left preparatory to the next stock feeding operation and during the period when the forward end of the stock is securely held by the collet, the rings of units B and C assume the position of the ring in Figure 2 against the compression of the spring, and release their hold on the stock bar during the retraction of the pusher assembly to the left. Since the unit A carried by the stock reel tube is fixed and is incapable of axial movement, and since the stock bar is held against backward movement by the collet, there will be no axial movement of the stock held by the unit A. f 1

Even if the stock bar in units B and C should slip in the colletor a slight backward movement of the bar tend to occur, there can be no actual backward movement of a stock bar in the pipe 27 because such movement would effectively be resisted and prevented by the ring and spring in unit A.

Thus it will readily be understood that by my invention intermittent automatic stock feed is provided when units such as A, B, and C are installed as explained above for each spindle of the machine.

In Figure 6 I have indicated on the pusher assembly the pusher spool 28 Whichis intended to be operated in the conventional manner by any suitable means. In Figure '7 one form of such means is illustrated as including a side rod 29 operatively connected at one end to conventional drum, cam roller and side lever 30. This rod operates a sliding latch member indicated generally at 3| which has engagement with the spool 28 on the pusher assembly.

Thus, when the rod 29 is actuated at each index of the spindle carrier, the latch engages the spool to retract the spool and pusher assembly to the left in Figures 6 and '7 preparatory to feeding the bar stock forwardlytoward the collet and tool.

By my invention waste of bar stock is materially reduced, the stock capacity for any given diameter pusher tube is greatly increased, and the stock holding rings and bushings may be of various inside diameters and may easily be interchanged in the tube to accommodate predetermined bar stock diameters.

My invention also provides for positive bar stock feed operation of the machine and is adaptable to automatic machines in which the feed is not to be continuous as well as to provide simple means for converting such machines into automatic continuous feed machines.

Various changes in the details of construction and arrangement of parts may be made without departing from the spirit of my invention or the scope of the appended claims.

I claim:

1. In stock feeding means, a tube through which the stock is fed an annulus in the tube and having side walls lying in intersecting planes and means in the tube exerting a lateral force against one of said annular side walls.

2. In stock feeding means, a tube through which the stock is fed an annulus in the tube and having side walls lying in intersecting planes and resilient means in the tube exerting a lateral force against one of said annulus side walls.

3. In stock feeding means, a tube through which the stock is fed an annulus in the tube and having side walls lying in intersecting planes and resilient means in the tube exerting a lateral force against one of said annulus side walls, said resilient means including a coiled spring.

4. In an automatic machine the combination with a pusher tube of a stock feeding pusher unit removably secured to an end of said tube, and comprising a tube, a bushing, a stock gripping ring, a spring for tilting said ring toward said bushing to grip bar stock passing through said ring and a member threaded into an end of the tube to engage said spring and whereby said bushing, ring, and spring may readily be removed axially of the tube.

5. A pusher tube feeding unit comprising a cylindrical body adapted to be mounted axially into an end of a pusher tube, the internal diameter of the unit being substantially that of the pusher tube upon which it is mounted, stock gripping means within the unit permitting relative movement between the stock and unit in one axial direction only, said stock gripping means including a tiltable ring encircling the stock and means exerting a pressure against the ring sufiicient to tilt the same slightly into stock gripping position.

6. In an automatic machine, intermittent stock feeding mechanism including a pusher tube, an aligned stock reel pipe, stock gripping means carried by said pusher tube to feed the stock toward a tool when the pusher tube is moved into that direction, but permitting reverse movement of the tube independently of the stock, and means carried by the pipe to grip the stock therein during such reverse movement of the tube said stock reel pipe in alignment with said tube, of stock feeding means, said stock feeding means comprising stock feeding units carried by said stock reel pipe and said pusher tube whereby successive stock lengths may be fed intermittently through the stock reel pipe and tube in but one direction in abutting end to end relation, one of said feeding units including a stock holding annulus tiltable transversely of its axis, and a resilient member for normally tilting said annulus into stock holding position.

9. In an automatic machine the combination with a pusher tube, of an annulus in the tube and adapted to embrace bar stock fed through said tube, and means for exerting a pressure against said annulus to tilt the same to stock holding position, said annulus having a lateral projection near its outer periphery defining a fulcrum about which said annulus may be tilted.

10. In an automatic machine the combination with a pusher tube, of an annulus in the tube and adapted to embrace bar stock fed through said tube, and means for exerting a pressure against said annulus to tilt the same to stock holding position, the wall of said annulus defining the opening therein being serrated or roughened for biting engagement with the stock.

11. In an automatic machine the combination with a pusher tube, of an annulus in the tube and adapted to embrace bar stock fed through said tube, and means for exerting a pressure against said annulus to tilt the same whereby said annulus will bitingly engage the bar stock at substantially diametrically opposed points to feed the stock when the pusher tube is moved in one direction.

STODDARD B. MARTIN. 

